Merge branch 'linus' into sched/urgent

[~andy/linux] / init / Kconfig

diff --git a/init/Kconfig b/init/Kconfig
index 38899243213de78717bdae1f4ed2417cf6c9500b..a23da9f0180341dd0cb8809f6108a2911336897a 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -615,7 +615,7 @@ config SYSFS_DEPRECATED
        bool
 
 config SYSFS_DEPRECATED_V2
-       bool "enable deprecated sysfs features which may confuse old userspace tools"
+       bool "enable deprecated sysfs features to support old userspace tools"
        depends on SYSFS
        default n
        select SYSFS_DEPRECATED
@@ -1079,6 +1079,28 @@ config SLOB
 
 endchoice
 
+config MMAP_ALLOW_UNINITIALIZED
+       bool "Allow mmapped anonymous memory to be uninitialized"
+       depends on EMBEDDED && !MMU
+       default n
+       help
+         Normally, and according to the Linux spec, anonymous memory obtained
+         from mmap() has it's contents cleared before it is passed to
+         userspace.  Enabling this config option allows you to request that
+         mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
+         providing a huge performance boost.  If this option is not enabled,
+         then the flag will be ignored.
+
+         This is taken advantage of by uClibc's malloc(), and also by
+         ELF-FDPIC binfmt's brk and stack allocator.
+
+         Because of the obvious security issues, this option should only be
+         enabled on embedded devices where you control what is run in
+         userspace.  Since that isn't generally a problem on no-MMU systems,
+         it is normally safe to say Y here.
+
+         See Documentation/nommu-mmap.txt for more information.
+
 config PROFILING
        bool "Profiling support (EXPERIMENTAL)"
        help